• 대한수학회지
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• 제52권5호
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• pp.945-954
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• 2015

Let ${\lambda}_f(n)$ denote the n-th normalized Fourier coefficient of a primitive holomorphic form f for the full modular group ${\Gamma}=SL_2({\mathbb{Z}})$. In this paper, we are concerned with ${\Omega}$-result on the summatory function ${\sum}_{n{\leqslant}x}{\lambda}^2_f(n^2)$, and establish the following result ${\sum}_{\leqslant}{\lambda}^2_f(n^2)=c_1x+{\Omega}(x^{\frac{4}{9}})$, where $c_1$ is a suitable constant.

• 대한수학회보
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• 제48권6호
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• pp.1303-1314
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• 2011

We consider meromorphic solutions of q-difference equations of the form $$\sum_{j=o}^{n}a_j(z)f(q^jz)=a_{n+1}(z),$$ where $a_0(z)$, ${\ldots}$, $a_{n+1}(z)$ are meromorphic functions, $a_0(z)a_n(z)$ ≢ 0 and $q{\in}\mathbb{C}$ such that 0 < |q| ${\leq}$ 1. We give a new estimate on the upper bound for the length of the gap in the power series of entire solutions for the case 0 < |q| < 1 and n = 2. Some growth estimates for meromorphic solutions are also given in the cases 0 < |q| < 1. Moreover, we investigate zeros and poles of meromorphic solutions for the case |q| = 1.

• 대한수학회지
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• 제54권1호
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• pp.35-57
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• 2017

In this paper, we study the natural star-operation defined by the set of associated primes of principal ideals of an integral domain, which is called the g-operation. We are mainly concerned with the ideal-theoretic properties of this star-operation. In particular, we investigate DG-domains (i.e., integral domains in which each ideal is a g-ideal), which form a proper subclass of the DW-domains. In order to provide some original examples, we examine the transfer of the DG-property to pullbacks. As an application of the g-operation, it is shown that w-divisorial Mori domains can be seen as a Gorenstein analogue of Krull domains.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제28권1호
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• pp.42-45
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• 2002

Cultures of primary human alveolar bone-derived cells were established from alveolar bone chips obtained from normal individuals undergoing tooth extraction. These cells were expanded in vitro until passage 3 and used for the in vivo assays. Cells were loaded into transplantation vehicles, and transplanted subcutaneously into immunodeficient mice to study the capacities of human alveolar bone-derived cells to form bone in vivo. Transplants were harvested 12 weeks after transplantation and evaluated histologically. Of 10 human alveolar bone-derived cell transplants, two formed a bone-like tissue that featured osteocytes and mineral. Eight of the ten formed no osseous tissue. These results show that cells from normal human alveolar bone are capable of forming bone-like tissue when transplanted into immunodeficient mice.

• Journal of applied mathematics & informatics
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• 제26권5_6호
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• pp.889-900
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• 2008

The problem of scheduling n jobs on a single machine is considered when the machine is subject to stochastic breakdowns. The objective is to minimize the weighted squared deviation of job completion times from a common due date. Two versions of the problem are addressed. In the first one the common due date is a given constant, whereas in the second one the common due date is a decision variable. In each case, a general form of deterministic equivalent of the stochastic scheduling problem is obtained when the counting process N(t) related to the machine uptimes is a Poisson process. It is proved that an optimal schedule must be V-shaped in terms of weighted processing time when the agreeable weight condition is satisfied. Based on the V-shape property, two dynamic programming algorithms are proposed to solve both versions of the problem.

• 한국공작기계학회논문집
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• 제11권5호
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• pp.53-57
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• 2002

The chatter to raise grinding operating is reduce the precision and the quality. In this study, In reply to AE signal and the normal force generated in the grinding operating were measured (1) the amplitude in the mathematical model of the normal force is the form as to transform an exponential (2) the chatter growth is minus point of an exponent. (3) From the observed wheel aspect after the chatter growth, it was to investigated the concern of the chatter growth and the wheel life.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.661-665
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• 1996

An inverse kinemetics problem of a reclaimer which digs and transports ironstones or coals in the raw yard is investigated. Because of the special features of the reclaimer of which scooping buckets are attached around the rotating drum at the end of boom, kinematic redundancy occurs in determining the joint varialbes For a given reclaiming point in space the forward kinematics yields 3 equations, however the number of involved variables in the equations are four. A plane equation approximating the surface near a reclaiming point is obtained by considering 8 adjacent points surrounding the reclaiming point. One extra equation to overcome redunduncyis further obtained from the condition that the normal vector at a reclaiming point is perpendicular to the plane. An approximate solution for a simplified problem is first discussed, Numerical solution for the oritinal nonlinear porblem with a constraint equation is also investigated. Finally a closed form solution which is not exact but sufficiently close enough is proposed by exploiting geometric constraint.

• 산업경영시스템학회지
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• 제25권4호
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• pp.1-7
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• 2002

Statistical process control is used widely as an effective tool to solve the quality problems in practice fields. All the control charts used in statistical process control are parametric methods, suppose that the process distributes normal and observations are independent. But these assumptions, practically, are often violated if the test of normality of the observations is rejected and/or the serial correlation is existed within observed data. Thus, in this study, to screening process, the Combined Shewhart - CUSUM quality control chart is described and evaluated that used bootstrap method. In this scheme the CUSUM chart will quickly detect small shifts form the goal while the addition of Shewhart limits increases the speed of detecting large shifts. Therefor, the CSC control chart is detected both small and large shifts in process, and the simulation results for its performance are exhibited. The bootstrap CSC control chart proposed in this paper is superior to the standard method for both normal and skewed distribution, and brings in terms of ARL to the same result.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제23회 학술대회
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• pp.1-3
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• 1996

The characteristics of fretting wear are reviewed. Fretting damage depends on slip amplitude and classified into three groups: (1) an annular damage according to Mindlin's analysis at microslip region, (2) strong adhesive deformation without loose wear particles at the intermediate region, and (3) formation of fine oxide particles at the gross slip region. The critical slip amplitude of fretting is the boundary between (2) and (3). The boundary slip amplitude depends on normal load. The wear rate increases and saturates with increasing slip amplitude. But it is constant by considering the critical amplitude. The role of oxide particles are discussed. Three different actions are noted: accelerating wear, preventing wear and insignificant effect. The oxide shows two opposing effect depends on normal load and slip amplitude. This is related to the removal rate from the interface (abrasive action) and compaction rate at the interface to form a protective layer. The effect of oxidation is significant to determine the wear and friction. The diffusion of oxygen is restricted at the small amplitude. As a result, crack formation at the boundary is a predominant damage, related to fretting fatigue damage.

• Journal of Chest Surgery
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• 제27권4호
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• pp.313-317
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• 1994

Surgical treatment is possible for the obstructive form of hypertrophic cardiomyopathy and transaortic left ventricular septal myectomy and myotomy has been the procedure of choice. If coexisting intrinsic mitral valve disease exists, mitral valve replacement has been performed. But abnormal systolic anterior motion of anterior mitral leaflet[SAM] with intrinsic normal mitral valve disease is the typical feature of IHSS and we prefer not to replace mitral valve. 3 patients underwent transaortic myotomy and myectomy for IHSS with mitral regurgitation. 2 patients of them have coexisting intrinsic mitral valve diseases such as mitral valve vegetation and chorda rupture. Concomittent mitral valve replacement were performed. 1 patient shows SAM of mitral anterior leaflet but has intrinsic normal mitral valve morphologically and transepicardial echocardiogram and direct monitoring of pressure gradient during the operative procedure gives better information for subsided mitral regurgitation. Post operative course during the 12 months follow-up was uneventful.